ES6 map is throwing error on array of object

const normalizeEventTypes = nextProps.events.space_events.map(obj, i => 
     obj.id
)

I code obj is not defined, my array of object look like this

{
    "space_events": [{
            "id": 1,
            "name": "Anniversaries"
        },
        {
            "id": 2,
            "name": "Brand Rollout"
        }
    }]
}

am I missing something?